Acoustic shock absorber for telephone lines



March 23 1926..

W- H. T. HOLDEN I ACOUSTIC SHOCK ABSORBER FOR TELEPHONE LINE S Filed May 20 1b [me IN VE N TOR W1ZZ'170Zde/ 0 &

A TTORNE Y adding to the Patented Mar. 23, 1926.

UNITED sTATEs- A A 1,517,120 PATENT 'oFFiCE.

WILLIAM-H. '1. HOLDEN, OF BROOKLYN, NEW YORK, ASSIGNOR TO AMERICAN TELE-r PHONE 80 TELEGRAPH COMPANY,

A CORPORATION OF NEW YORK.

ACOUSTIC SHOCK ABSORBER FOR TELEPHONE LINES.

To all whom it may concern: Be it known that 1, WILLIAM H. T. HOLDEN, residing at. Brooklyn, in the county of Kings and State of New York, have invented certain Improvements in Acoustic Shock Absorbers forTelephone Lines," of which the following is a specification.

This invention relates to means for eliminating clicks due to switching on common battery telephone lines, and more particularly to means for eliminating clicks due to switching on common battery telephone lines employing repeating coil battery feed.

The principal purpose of the invention is to prevent the acoustic shock to telephone operators which is caused by switchhook operation or ,byswitching operation at the central oifice. 4 V

Applicants invention consists broadly in talking windings of the repeating coil .used on telephone lines employing repeating coil battery feed, a fifth windm of relatively high impedance having a sultable discharge tube connected across its.

terminals. n

Applicants invention will be more clearly understood when the following'detailed description of one desirable form of embodiment is read with reference to the accompanying drawing, which shows'the specific Qembodiment in circuit diagram.

With reference to the details of the drawthe repeating coil shown has four talkfifth protective winding with i terminals 9 mid 10. The four talking windings have each the usual impedance, inductance, etc.,

of a standard repeating coil winding; Terminals 2 and 3 are connected to at terminals -1 and 4 are connected to line, termi nals 6 and 7- are connectedto battery or to condensers, and terminals 5 and 8 are connected to line or trunk circuit, as is well understood in the art.

The fifth winding, the protective winding, has a high turn ratio to each talking winding, this ratio being preferably as great as the reasonable limits of size oi? the coil will permit. The resistance of this winding should not exceed 500 ohms. The lowest desirable ratio of the impedances of the pro-- tcctive winding and of one of the talking windings is 20 to 1. Across the terminals 9 and 10 of the fifth coil winding there is contery,

Application file d May 20, 1924. Serial N... 714,696.

nected a discharge tube 11. This tube should i have the characteristics of rapid breakdown and small. time lag. A desirable vdischarge device is the small tubular bulb designed and used to kill the spark at relay contacts upon the opening of highly sensitive cir cuits. This bulb contains two parallel plate electrodes mounted with a very slight separating space between them and is filled with commercial argon at a pressure of about 100 millimeters o'f'mer-cury,

The operation of applicants device is briefly described as follows: When there ocours in the talking windings a sudden change of currentsuch as that caused by switchingthe result is a high voltage in the fifth or protective winding, and the discharge tube is operated, thus absorbing the ener which otherwise would cause clicks in t e telephones fed from the repeating coil.

It is to be understood that the s ecific embodiment of applicants invention erein described may be modified within the true 1. In association with a telephone line, a

repeating coil comprising a plurality of talking windings of relatively low impedance and an additional winding of relatively high impedance, and a discharge device connect; ed across the terminals of the high impedance winding.

2. In association with common battery telephone lines employing repeating coil battery feed, a repeating coilcomprisinga plurality of talking windings of relatively low impedance andan additional winding of relatively high impedance, and a discharge tube connected across the terminals of the high impedance winding.

3. In association with a telephone line, a

repeating coil comprising a plurality of talking windings having a relatively small'number of turns and a protective winding hav-' ing a relatively large number of turns, and a discharge device connected across the terminals of said protective winding.

4. In association with common battery telephone-lines employing repeating coil battery feed, a repeating coil comprising a plurality of talking windings having a relatively small number of turns and a protective winding having a relatively large number of turns, and a discharge-tube connected across the terminals of said protective wind- 5. As means for eliminating acoustic shocks due to switching on common battery telephone lines employing repeating coil battery feed, a protective winding in association with the repeating coil talking windings, and a discharge tube connected across the terminals of the protective winding, said protective winding having a high turn ratio to the talking windings. v

6. In association with a telephone line, a repeating coil comprising four talking windings of relatively low impedance and a fifth winding of relatively high impedance, and a discharge device connected across the terminals of said fifth winding.

7. In association with common battery telephone lines employing repeating coil hattery feed, a repeating coil comprising four talking windings of relatively low impedance and a fifth winding of relatively high impedance, and a discharge tube connected across the terminals of said fifth winding.

8. In association with a telephone line, a

repeating coil comprising four talking windings and-a protective winding said protective winding having a high turn ratio to said talking windings, and a discharge device connected across the terminals of said protective winding.

9. In association with common battery telephone lines employing repeating coil battery feed, a repeating coil comprising four talking windings and a protective winding, said protective winding having a high turn ratio to said talking windings, and a discharge tube connected across the terminals of said protective winding.

10. Means for eliminating acoustic shocks due to switching on common battery telephone lines employing repeating coil battery feed, said means consisting of a protective winding of relatively high impedance associated with the repeating coil talking windings, and a discharge tube connected across the terminals of said protective windin a In testimony whereof, I have signed my name to this specification this 17th day of May 1924:-

. WILLIAM H. T. HOLDEN. 

